Dancing is an ancient art form found in cultures around the world. All forms of dance incorporate elements of rhythm, symmetry, repetition, exaggeration, and grace of movement. In the simplest forms of dance, these elements of rhythm, symmetry, repetition, exaggeration, and grace all are incorporated in movement of the dancer's hands and feet, with dancer's torso and limbs tending to follow movements and participate in the exercise.
As different forms and expressions of dance have evolved over the years, dancers have progressed from the ordinary, everyday sorts of movements to movements derived from actions at the edge of human endurance and athletic ability. Ballet first employed such impressive, exaggerated movements that tested the limits of the dancer's physical capabilities. Modern dance builds on the dramatic movements of classical ballet and further pushes the limits of human endurance and ability.
Ballet and modern movements can include periods of running, jumping, spinning, leaping, and physical interactions among several individuals. Virtually any ballet or modern dance exercise or performance can be physically punishing, and dancers can experience many injuries over the years. In fact, few dancers can meet the rigorous performance standards of professional dance into middle age. Dancers frequently suffer sore muscles, inflamed skin, or even cracked and bleeding feet.
The driving desire to achieve extremes in movement in ballet has spawned the development of footwear meant to facilitate graceful and inspiring movements, such as rotating on only a single toe or walking and landing on the toes, even if these movements are not natural movements for the average person. Ballet footwear enables these dance steps and can help protect the dancer's feet by distributing forces and pressures resulting from dance steps over a wide area of the outside surface of the foot and by addressing foot-to-surface or shoe-to-surface frictional requirements. The purpose of dance shoes is to achieve a balance between traction and sliding, as may be required in ballet or dance movements.
Conventional ballet slippers typically enclose the dancer's entire foot with a silky or satiny fabric having a charmeuse finish. In many forms of dance, including ballet and modern dance, a “barefoot” look is preferred, or even required. Conventional ballet slippers are designed to fit snugly against the dancer's skin, but no matter how tightly against the dancer's feet the ballet slippers fit, the slippers can still be seen. In modern dance, the desire or requirement for a truly barefoot look can be so strong that dancers wear no footwear at all, even though dancers will subject their feet to physical punishment from impacts, pulls, twists, and abrasions, or will not have the advantage of shoe-to-surface contact via a slipper or shoe that addresses the frictional requirements of the movements to be performed.
Shoes with split soles and/or uppers that expose a portion of the wearer's foot do exist. For example, Canadian patent number 1077711 and Swiss patent number 168702 describe overshoes having split soles and uppers joined together by an arrangement of straps. In embodiments having split soles and/or uppers, these shoes offer two basic types of connecting straps. The first type is a pair of connecting straps lying along the plantar surface of the shoe that joins the portions of the sole (see FIG. 4 of Canadian patent number 1077711 and FIGS. 1, 3, and 5 of Swiss patent number 168702). This pair of straps can be used alone or in combination with a second type of strap that stretches along the sides of the shoe. This second type of connecting strap can be a single, u-shaped strap that wraps from the front of the shoe around the heel (see FIG. 4 of Canadian patent number 1077711) or a pair of individual straps that connect the front and rear portions of the shoe along its sides (FIGS. 4 and 5 of Swiss patent number 168702). Importantly, these straps provide tensioning largely, or almost entirely, along the longitudinal axis of the foot or shoe (i.e., along the axis running from toes to heel, described as the Y-axis below) and they can obscure a significant portion of the side or top of the foot.